基于AlGaAs分布布拉格反射器增强的GaAs/AlGaAs的850nm波长单行载流子光电探测器

A uni-traveling-carrier photodiode based on GaAs/AlGaAs enhanced by AlGaAs distributed Bragg reflector at 850 nm wavelength

摘要:

高速 850 nm GaAs/AlGaAs面入射型单行载流子光电探测器(PD)是短距离光链路中的重要器件,面临着带宽和响应度之间的相互矛盾。我们报道了一种基于分布布拉格反射器(DBR)增强的 GaAs/AlGaAs 的单行载流子光电探测器(UTC-PD)。DBR由20个周期的高/低Al组分的AlxGa1-xAs三元合金组成,可以在830~870 nm范围内形成>0.9的反射。在AlGaAs DBR的增强下,我们将GaAs吸收层所需的厚度降低到1040 nm,兼顾PD对光的吸收率和光生电子的渡越时间。我们采用双台面、聚合物平面化、共面波导电极结构制作了UTC-PD器件。该器件在850 nm波长、-2V偏压下具有19.26 GHz 的 -3dB 带宽和0.4926 A/W 的响应度。

Abstract:

GaAs/AlGaAs surface-illuminated Uni-Traveling-Carrier (UTC) photodiode (PD) is an important device in short-range optical links. However, it faces the contradiction between bandwidth and responsiveness. We report a GaAs/AlGaAs UTC-PD enhaced by Distributed Bragg Reflector (DBR) which consists of 20 cycles of high/low Al component AlxGa1-xAs and it has the reflectance of >0.9 in the wavelength of 830~870 nm. The thickness of the GaAs absorption layer is reduced to 1040 nm which compromises the light absorption of PD and the transit time of photogenerated electrons. The UTC-PD device is fabricated with the structure of double mesa, polymer planarization and coplanar waveguide electrode. The device has a -3dB bandwidth of 19.26 GHz and a responsivity of 0.4926 A/W at the wavelength of 850 nm and a bias of -2V.